MEDIA ROLL HOLDER
In one example, a holder for a media roll includes a first support to support a first end of the roll, a second support to support a second end of the roll, and a shifter to change the distance between the first support and the first end of the roll without changing the distance between the second support and the second end of the roll.
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In some inkjet printers, a media wide printhead assembly that remains stationary during printing, commonly called a print bar, is used to print on paper or other print media moving past the print bar.
The same part numbers designate the same or similar parts throughout the figures.
DESCRIPTIONPrint bars are susceptible to print quality defects caused by the uneven use of the fluid dispensing elements in the print bar. For example, when printing documents with a long recurring image (e.g., engineering drawings with a standard border), some of the fluid dispensing elements are used for the full length of every page while other elements are used much less often. For another example, printing on wider media after extended printing on narrower media re-activates elements that have been inactive for long periods. Over time, the uneven use of the fluid dispensing elements can cause visible print quality defects and lead to the premature failure of over-used elements.
A new holder has been developed for roll type print media to vary the position of the media for more even use of the fluid dispensing elements. In one example, the holder includes a first support to support a first end of the roll, a second support to support a second end of the roll, and a shifter to change the distance between the first support and the first end of the roll without also changing the distance between the second support and the second end of the roll, allowing a shift in the position of the media roll with respect to the print bar. In one implementation for the shifter, the hub assembly at the first support includes an adjustable spacer operatively connected to the hub and an actuator to adjust the position of the spacer to vary the distance between the hub and the first support, thus shifting the position of the media roll. Shifting the position of the media roll periodically helps reduce the risk of defects caused by the uneven use of fluid dispensing elements in the print bar.
While examples are described with reference to a print media roll in a printer, examples are not limited to printers or rolls of print media but may be implemented in other devices for other types of media rolls.
As used in this document, a “printhead” means that part of an inkjet printer or other inkjet type dispenser for dispensing fluid from one or more openings, for example as drops or streams; and a “print bar” means a structure or device holding an arrangement of one or more printheads that remains stationary during printing. “Printhead” and “print bar” are not limited to printing with ink but also include inkjet type dispensing of other fluids and/or for uses other than printing.
Printer 10 also includes edge detectors 32, 34 connected to a controller 36. Controller 36 represents generally the electronic instructions, processors and associated memories, and the electronic circuitry and components needed to control the operative elements of a printer 10, including print bar 24. For example, controller 36 may adjust printhead control data to print the desired image based on the actual position of web 20 signaled by detectors 32, 34. Accordingly, when media web 20 is shifted laterally with respect to print bar 14 (and thus printheads 16) by adjusting the position of roll 22 on holder 12, detectors 32, 34 signal the new position of web 20 so that controller 36 can adjust the printhead control data to account for the shift, including using more or fewer or different dispensing elements in printheads 16.
Holder 12 also includes a shifter 50 to shift roll 22 along axis 46. In the example shown in
In the example shown in
Each support 38, 42 includes a hub 54, 56 mounted to a car 58, 60. Each hub 54, 56 is mounted on an axle with a bushing or other suitable structure that allows each hub 54, 56 (and thus roll 22) to rotate around axis 46. Also, hub 54 is part of a hub assembly 62 that includes an adjustable spacer (not shown in
A wedge shaped guide 66 helps guide each end 40, 44 of roll 22 on to hubs 54, 56. Holder 12 also includes a shifter 50 to shift roll 22 along axis 46. Shifter 50 includes an adjustable spacer in hub assembly 62 that moves hub 54 linearly along axis 46 with respect to car 58, and supports 38 and 42 that are movable along axis 46, Hub 56 in the movable second support 42 is stationary linearly along axis 46 with respect to car 60.
The structure and operation of one example of a shifter 50 with adjustable spacer 52 will now be described in detail with reference to
Referring first to
Huh assembly 62 includes an actuator 84 to move spacer 52 forward and rearward to push out hub 54 and pull in hub 54, respectively. In the example shown, actuator 84 includes a helical groove 86 along the outer circumference of spacer 52, pins 88 that ride in groove 86, and a wheel 90 to drive pins 88. Adjusting wheel 90 rotates on a cylindrical axle 92 that is fastened to car back plate 93 with, for example, hooks 94. Wheel 90 is retained in position on axle 92, for example, with a retainer 96 and fasteners 98. Pins 88 and groove 86 act like a lead screw to convert the rotary motion of wheel 90 to linear motion of spacer 52 along axis 46. Other types of cams, cranks, and screws, for example, may be suitable rotary-to-linear motion converters for actuator 84.
Wheel axle 92 also fastens spacer 52, hub 54 and hub axle 68 to car back 93 and prevents spacer 52 and axle 68 from rotating. Keys 100 on the inner circumference of cylindrical wheel axle 92 fit into keyways 102 on spacer 52 (which is integral to axle 68) to prevent spacer 52 and axle 68 from rotating. Actuator pins 88 in groove 86 in spacer 52 determine the axial position of spacer 52 and axle 68, and thus hub 54, with respect to back plate 93. Hooks 94 fasten the entire hub assembly 54 to car 58 through plate 93, thus varying the axial distance between hub 54 and the back 83 of car 58.
The sequence of views in
In the example shown, groove 86 extends continuously around the full circumference of spacer 52 alternately angled forward and rearward for each 90° of rotation for reciprocal linear motion so that spacer 52 and hub 54 may be adjusted in and out while rotating wheel 90 in just one direction. This configuration for groove 86 may be desirable, for example, when a ratcheting mechanism is employed to turn wheel 90 as described below with reference to
For a shifter 50 operated directly by a user, the user must remember or be prompted to periodically operate shifter 50 to promote printhead health by distributing use evenly across of all fluid dispensing elements. The challenge of getting the user to regularly operate shifter 50 is made more challenging by the fact that shifting the media roll is not obviously related to printhead health. To help meet this challenge, the operation of shifter 50 may be linked to loading and unloading a media roll. For example, shifter 50 may be linked to a brake that keeps the car parked during printing but releases the car to move for loading and unloading a media roll.
As noted at the beginning of this Description, the examples shown in the figures and described above illustrate but do not limit the invention. Other examples are possible. Therefore, the foregoing description should not be construed to limit the scope of the invention, which is defined in the following claims.
Claims
1. A hub assembly to hold one end of a media roll, the hub assembly including:
- a hub to engage the roll, the huh rotatable on an axis;
- a spacer operatively connected to the hub to vary a distance along the axis between the hub and a support supporting the hub; and
- an actuator to move the spacer along the axis to vary the distance between the hub and the support.
2. The hub assembly of claim 1, wherein the actuator is to move the spacer along the axis toward and away from the support to vary the distance between the hub and the support.
3. The hub assembly of claim 2, wherein the actuator includes:
- a rotatable wheel that is stationary along the axis; and
- a converter between the wheel and the spacer to convert rotary motion of the wheel into linear motion of the spacer.
4. The hub assembly of claim 3, wherein the converter includes:
- a groove in the spacer not parallel to the axis; and
- a pin rotatable with the wheel and extending into the groove to move the spacer linearly with rotation of the wheel.
5. The hub assembly of claim 4, wherein the groove extends continuously around the spacer alternatively toward and away from the support to move the spacer back and forth away from and toward the support, respectively.
6. A holder for a media roll, the holder including:
- a first support to support a first end of the roll;
- a second support to support a second end of the roll; and
- a shifter to change a first distance between the first support and the first end of the roll without changing a second distance between the second support and the second end of the roll.
7. The holder of claim 6, wherein the shifter is to increase the first distance without changing the second distance and to decrease the first distance without changing the second distance.
8. The holder of claim 7, wherein the shifter includes the second support movable a third distance in response to changing the first distance.
9. The holder of claim 8, wherein the second support is movable a third distance equal to a change in the first distance.
10. The holder of claim 8, wherein the shifter includes the first support movable a fourth distance in response to changing the first distance.
11. The holder of claim 10, wherein a sum of the third distance and the fourth distance equals a change in the first distance.
12. The holder of claim 11, wherein the shifter includes a link between the first support and the second support to move each support an equal distance in response to changing the first distance.
13. A holder to hold a roll of print media along an axis in a printer with a stationary print bar, the holder including:
- a first car carrying a first hub to mount a first end of the roll, the first car movable linearly along the axis and the first hub rotatable around the axis and movable linearly relative to the first car;
- a second car carrying a second hub opposite the first hub to mount a second end of the roll, the second car movable linearly along the axis and the second hub rotatable around the axis and not movable linearly relative to the second car; and
- a shifter to shift the position of the roll with respect to the print bar by moving the first hub along the axis relative to the first car and changing a distance along the axis between the cars.
14. The holder of claim 13, wherein the shifter includes:
- a spacer operatively connected to the first hub to define a first distance along the axis between the first hub and the first car and an actuator to move the spacer along the axis to change the first distance; and
- a first link between the first car and the second car to automatically change a second distance along the axis between the cars proportional to a change in the first distance.
15. The holder of claim 14, wherein the actuator includes a rotatable wheel that is stationary along the axis and a converter between the wheel and the spacer to convert rotary motion of the wheel into linear motion of the spacer.
16. The holder of claim 15, including: wherein
- a brake to immobilize the first car; the brake movable between an engaged position in which the first car cannot move along the axis and a disengaged position in which the first car can move along the axis;
- a handle to move the brake between engaged and disengaged positions; and
- the shifter includes a second link between the brake handle and the wheel to turn the wheel in response to the handle moving the brake from an engaged position to a disengaged position or from a disengaged position to an engaged position.
17. The holder of claim 16, wherein the second link includes a ratchet having a pawl connected to the handle and a gear connected to the wheel.
Type: Application
Filed: Jun 5, 2014
Publication Date: May 25, 2017
Patent Grant number: 10301132
Applicant: HEWLETT-PACKARD DEVELOPMENT COMPANY, L.P. (Houston, TX)
Inventors: Daniel GONZALEZ PERELLO (Terrassa), Joaquim BRUGUE GARVI (Barcelona), Felix RUIZ MARTINEZ (Sant Cugat del Valles), Xavier ALONSO BECERRO (Sant Cugat del Valles)
Application Number: 15/314,894